http://www. is best to your site and it is an advange if you want to have others subdomains later. http://www.yourdomain.com http://blog.yourdomain.com http://forum.yourdomain.com and if you want to seo-target other country, other language and you do not want to buy countries domains, then http://fr.yourdomain.com (France) http://uk.yourdomain.com (UK) etc... I thing http://www. is better.
google sees both www.g4hq.com g4hq.com as the same, overall i would keep it at www. << makes it look more pro